Ultrasonic liquid treatment system

ABSTRACT

An ultrasonic treatment chamber and a process for ultrasonically treating a liquid in an ultrasonic treatment chamber include an elongate, generally tubular housing having an inlet and an outlet spaced longitudinally from the inlet. Liquid is directed into the housing at the housing inlet for longitudinal flow within the housing to the housing outlet. Mechanical ultrasonic vibration is generated within the housing in direct contact with the liquid flowing within the housing, with the direct contact being upstream of the housing outlet. A standing acoustic wave is produced within the housing with the standing acoustic wave having a node spaced longitudinally from the housing outlet.

FIELD OF INVENTION

This invention relates generally to systems for ultrasonically treatinga liquid, more particularly for ultrasonically treating a flowing liquidin a treatment chamber in which particulate material is present in thechamber.

BACKGROUND

Liquid reaction or treatment chambers find numerous applications forenhancing the treatment of liquids such as a single component liquid,liquid-liquid reaction and/or mixing, liquid-gas reaction and/or mixingand liquid-particulate material reaction and/or mixing. For example, informulating inks, paints and other viscous materials two or morecomponents (at least one being a liquid) are mixed together in such atreatment chamber to form the applicable solution. Other examplesinclude the simultaneous introduction of various liquids and gases intothe chamber to promote certain reactions. This would include the flow ofwater into the chamber with the introduction of gases such as air and/oroxygen and/or ozone only to mention a few. Also such chambers can beused to induce a variety of chemical reactions such as the decompositionof hydrogen peroxide, emulsion polymerization reactions and the creationof emulsions for emulsion polymerization mechanisms.

In other applications, treatment chambers can be used for thedeagglomeration of particles in a liquid stream. This would include thedeagglomeration of nano-particles such as pigments used in theformulation of inks. Plus the simultaneous formulation of an ink usingthese nano-pigment particles. This system can also have the simultaneousexposure to UltraViolet (UV) light to promote certain reactions offluids or fluid/gas or fluid/gas/solids systems in the ultrasonicchamber. Another application could be in the medical field where atreatment chamber is used in the preparation of pharmaceuticalformulations that are composed of powders/liquids and liquids fordispensing for use.

In particular, it is often advantageous to provide the chamber with someagitating mechanism by which liquid is agitated within an elongatecolumn or chamber. By agitating the liquid, a desired reaction (e.g.,mixing or other result) may be expedited and thus capable of beingachieved in a continuous flow operation. As a result, treatment chambersthat facilitate such agitation are particularly useful in continuousflow treatment processes.

Agitation of a liquid may be referred to as static agitation, in whichagitation is caused by the particular flow parameters (e.g., flow rate,pressure, etc.) of the one or more liquid components through a column.Static agitation may also occur by directing a flow of liquid paststationary agitating members, such as a helical vane-type constructionor other structures disposed in the flow column or chamber that disruptand thus turbulate the flow of the liquid to be treated. Dynamicagitation is brought about by moving, e.g., rotating, oscillating,vibrating, etc. one or more agitating members (e.g., vanes, fan blades,etc.) within the treatment chamber through which the liquid flows.

One particularly useful type of dynamic agitation of the liquid resultsfrom ultrasonic cavitation, a more rigorous agitation, in the liquid.Ultrasonic cavitation refers to the formation, growth and implosivecollapse of bubbles in liquid due ultrasonic energization thereof. Suchcavitation results from pre-existing weak points in the liquid, such asgas-filled crevices in suspended particulate matter or transientmicrobubbles from prior cavitation events. As ultrasound passes througha liquid, the expansion cycles exert negative pressure on the liquid,pulling the molecules away from one another. Where the ultrasonic energyis sufficiently intense, the expansion cycle creates cavities in theliquid when the negative pressure exceeds the local tensile strength ofthe liquid, which varies according to the type and purity of liquid.

Small gas bubbles formed by the initial cavities grow upon furtherabsorption of the ultrasonic energy. Under the proper conditions, thesebubbles undergo a violent collapse, generating very high pressures andtemperatures. In some fields, such as what is known as sonochemistry,chemical reactions take advantage of these high pressures andtemperatures brought on by cavitation. However, the growth and violentcollapse of the bubbles themselves provides a desirably rigorousagitation of the liquid. Cavitation that occurs at the interface betweenthe ultrasonically energized liquid and a solid surface is ratherasymmetric and generates high speed jets of liquid, further agitatingthe liquid. This type of cavitation is particularly useful, for example,in facilitating a more complete mixing together of two or morecomponents of a liquid solution.

It is known to pack some treatment chambers with a bed of particles,such as in the manner of a fluidized bed reactor. The particles are thusin the flow path of the liquid within the treatment chamber and furtherfacilitate treatment of the liquid. However, where such particles arepresent in the chamber, the chamber must be configured to prevent theparticles from being carried (or forced) out of the chamber by theliquid flowing therein. For example, a screen element may block theoutlet of the chamber to block the particles, but not the liquid, fromexiting the chamber. While such a screen element can be effective, thereis a risk that the particles will agglomerate or otherwise build up onthe screen element and reduce the flow rate of the liquid out of thechamber, thereby increasing the pressure in the chamber.

There is need, therefore, for a continuous flow ultrasonic liquidtreatment chamber that takes advantage of the benefits of ultrasonicenergy to treat a flowing liquid, particularly where particles are usedin such a treatment chamber, while maintaining desired operationconditions of the treatment chamber.

SUMMARY

In one embodiment, an ultrasonic treatment chamber for ultrasonicallytreating a liquid generally comprises an elongate housing havinglongitudinally opposite ends and an interior space, with the housingbeing generally closed at its longitudinal ends and having an inlet portfor receiving liquid into the interior space of the housing and anoutlet port through which liquid is exhausted from the housing followingultrasonic treatment of the liquid. The outlet port is spacedlongitudinally from the inlet port such that liquid flows longitudinallywithin the interior space of the housing from the inlet port to theoutlet port. An elongate ultrasonic waveguide assembly extendslongitudinally within the interior space of the housing and is operableat a predetermined ultrasonic frequency to ultrasonically energizeliquid flowing within the housing. The waveguide assembly generallycomprises an elongate ultrasonic horn disposed intermediate the inletport and the outlet port of the housing and having an outer surfacelocated for contact with liquid flowing within the housing from theinlet port to the outlet port. The waveguide assembly has a terminal endspaced longitudinally from the outlet port of the housing. A standingwave member is disposed within the housing longitudinally intermediatethe outlet port of the housing and the terminal end of the waveguideassembly. The standing wave member is spaced from the terminal end ofthe waveguide assembly so as to define an acoustic standing wavetherebetween upon operation of the waveguide assembly at thepredetermined ultrasonic frequency.

In another embodiment, an ultrasonic treatment system for ultrasonicallytreating a liquid generally comprises an elongate, generally tubularhousing having longitudinally opposite ends and an interior space. Thehousing has an inlet for receiving liquid into the interior space of thehousing and an outlet through which liquid is exhausted from the housingfollowing ultrasonic treatment of the liquid. The outlet is spacedlongitudinally from the inlet such that liquid flows longitudinallywithin the interior space of the housing from the inlet to the outlet.An elongate ultrasonic horn extends longitudinally within the interiorspace of the housing intermediate the inlet and the outlet of thehousing. A drive system is operable to ultrasonically vibrate theultrasonic horn, with the ultrasonic treatment system being configuredsuch that operation of the drive system generates mechanical vibrationof the horn within the interior space of the housing and furthergenerates a standing acoustic wave within the interior space of thehousing.

In one embodiment of a process for ultrasonically treating a liquid inan ultrasonic treatment chamber comprised of an elongate, generallytubular housing having an inlet and an outlet spaced longitudinally fromthe inlet, liquid is directed into the housing at the housing inlet forlongitudinal flow within the housing to the housing outlet. Mechanicalultrasonic vibration is generated within the housing in direct contactwith the liquid flowing within the housing, with the direct contactbeing upstream of the housing outlet. A standing acoustic wave isproduced within the housing with the standing acoustic wave having anode spaced longitudinally from the housing outlet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of one embodiment of a system for ultrasonicallytreating a liquid;

FIG. 2 is a side elevation of an ultrasonic treatment chamber of thesystem of FIG. 1, with a bed of particles omitted from the treatmentchamber;

FIG. 3 is a longitudinal (e.g., vertical) cross-section of theultrasonic treatment chamber of FIG. 2;

FIG. 3A is an enlarged, fragmented view of a portion of thecross-section of FIG. 3;

FIG. 3B is a top plan view of a collar that forms part of the housing ofthe ultrasonic treatment chamber of FIG. 2;

FIG. 4 is a front perspective of an alternative embodiment of a hornassembly; and

FIG. 5 is a schematic cross-section of the ultrasonic treatment chambersimilar to that of FIG. 3 during operation according to one embodimentof a process for ultrasonically treating a liquid.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

DETAILED DESCRIPTION

With reference now to the drawings, and in particular to FIG. 1, in oneembodiment a system for ultrasonically treating a liquid generallycomprises an ultrasonic treatment chamber, generally indicated at 21,that is operable to ultrasonically treat a liquid with both mechanicalvibration and with a standing acoustic wave. The term “liquid” as usedherein is intended to refer to a single component liquid, a solutioncomprised of two or more components in which at least one of thecomponents is a liquid such as a liquid-liquid mixture, a liquid-gasmixture or a liquid in which particulate matter is entrained, or otherviscous fluids.

The ultrasonic treatment chamber 21 is illustrated schematically in theembodiment of FIG. 1 and described further herein with reference to useof the treatment chamber generally in the manner of a packed bed orfluidized bed reactor in which the chamber is packed at least in partwith particulate matter (broadly referred to herein as chamber particles24), typically spherically shaped beads or particles, for treatingliquid as the liquid passes through the chamber. In the particularembodiment illustrated in FIG. 1, a liquid treatment system 23 isconfigured to utilize the ultrasonic treatment chamber 21 for mixingtogether two or more components of a liquid solution.

For example, some contemplated mixing uses for the ultrasonic treatmentchamber 21 include, without limitation, mixing resins and curing agentsfor the plastic industry; mixing pulp slurries with chemical additivessuch as bleaching agents, wet strength agents, starches, dyes, enzymes,fillers, anti-slime agents, silicone additives, etc.; mixing compoundsused in the paper and tissue industries, such as clay slurries forcoatings, polymeric additives such as wet strength resins, starchsuspensions, silicone compounds, lotions, filler suspensions, etc.;mixing resins and coloring agents, fillers, and other compounds; mixingimmiscible phases to prepare emulsions, such as food emulsions (e.g.,for sun block products, hand lotions, lipstick compounds, etc.),cosmetics, cleaning agents (including nanoemulsions of oil and water),pharmaceutical compounds, etc; and mixing coloring agents and othercompounds to form cosmetics such as hair dyes; mixing pulp slurries withchemical additives such as bleaching agents, wet strength agents,starches, dyes, etc.; and mixing compounds used in the paper and tissueindustries, such as clay slurries.

It is understood, however, that the ultrasonic liquid treatment chamber21 may be used with liquid ultrasonic treatment systems other than formixing but where passing a liquid through a bed of particulate materialat least in part comprises the desired treatment of the liquid.Non-limiting examples include food processing and treatment; degassingsolutions (e.g., pulling dissolved gasses from liquid solutions such asoxygen, nitrogen, ammonia, etc.); and enhancing chemical reactions, forexample, as is common in sonochemistry where excitation is imparted to achemical reaction to expedite the reaction.

Additional examples include degassing a mixture to simplify subsequenttreatment and reduce void formation; deinking recycled papermakingfibers, in which ultrasonic energy may assist in removal of inks(particularly in the presence of enzymes, detergents, or otherchemicals); hydrogenating oils, cheese, or other food stuffs, in whichgas and slurries or liquids must be mixed; homogenizing milk and othercompounds; treating wastewater and/or manure, in which a variety ofadditives and air bubbles may need to be mixed with a slurry;manufacturing petrochemicals such as lubricant mixtures, gasolineblends, wax mixtures, etc., and compounds derived from petrochemicals;processing dough (e.g., mixing combinations of agents to be added toflour or processing the dough itself, which may result in improvedbreakdown of gluten, etc.). The ultrasonic treatment chamber 21 may alsobe used in chemical reactors involving single or multiple phases,including slurries.

In other contemplated uses, the ultrasonic treatment chamber 21 may beused to remove entrapped gas bubbles from coating solutions that areused in gravure coating, meyer rod coating or any other coatingapplications where it is desirable to remove air bubbles from asolution. The ultrasonic treatment chamber 21 may also be used to removeliquid or solid material from a solution, such as where the chamberparticles comprise an adsorbent material.

In particular, the ultrasonic treatment chamber 21 is suitable for usein liquid treatment systems in which ultrasonic treatment of the liquidis desired in an in-line, e.g., continuous flow process in which fluidflows continuously through the chamber. It is contemplated, though, thatthe treatment chamber 21 may be used in a liquid treatment system inwhich liquid is treated in accordance with a batch process instead of acontinuous flow process and remain with the scope of this invention.

In the illustrated embodiment of FIG. 1, the ultrasonic treatmentchamber 21 is generally elongate and has an inlet end 25 (a lower end inthe orientation of the illustrated embodiment) and an outlet end 27 (anupper end in the orientation of the illustrated embodiment). The system23 is configured such that liquid enters the treatment chamber 21generally at the inlet end 25 thereof, flows generally longitudinallywithin the chamber (e.g., upward in the orientation of illustratedembodiment) and exits the chamber generally at the outlet end of thechamber.

The terms “upper” and “lower” are used herein in accordance with thevertical orientation of the ultrasonic treatment chamber 21 illustratedin the various drawings and are not intended to describe a necessaryorientation of the chamber in use. That is, while the chamber 21 is mostsuitably oriented vertically, with the outlet end 27 of the chamberabove the inlet end 25 as illustrated in the various drawings, it isunderstood that the chamber may be oriented with the inlet end above theoutlet end, or it may be oriented other than in a vertical orientationand remain within the scope of this invention.

The terms axial and longitudinal refer directionally herein to thelengthwise direction of the chamber 21 (e.g., end-to-end such as thevertical direction in the illustrated embodiments). The termstransverse, lateral and radial refer herein to a direction normal to theaxial (e.g., longitudinal) direction. The terms inner and outer are alsoused in reference to a direction transverse to the axial direction ofthe ultrasonic treatment chamber 21, with the term inner referring to adirection toward the interior of the chamber (e.g., toward thelongitudinal axis of the chamber) and the term outer referring to adirection toward the exterior of the chamber (e.g., away from thelongitudinal axis of the chamber).

The inlet end 25 of the ultrasonic treatment chamber 21 is in fluidcommunication with a suitable delivery system, generally indicated at29, that is operable to direct one or more liquid components to, andmore suitably through, the chamber 21. For example, in the illustratedtreatment system 23 of FIG. 1 the delivery system 29 comprises aplurality of pumps 31 (such as one pump for each component of thesolution to be mixed in the chamber) operable to pump the respectivecomponents from a corresponding source (illustrated schematically inFIG. 1 as reference number 32) thereof to the inlet end 25 of thechamber 21 via suitable conduits (illustrated schematically in FIG. 1 asreference number 33). As an example, four such pumps 31, componentsources and corresponding conduits 33 are shown in FIG. 1.

It is understood that the delivery system 29 may be configured todeliver less than four (including one), or more than four components tothe treatment chamber 21 without departing from the scope of thisinvention. It is also contemplated that delivery systems other than thatillustrated in FIG. 1 and described herein may be used to deliver one ormore components to the inlet end 25 of the ultrasonic treatment chamber21 without departing from the scope of this invention.

With reference now to FIG. 2, the ultrasonic treatment chamber 21 of theliquid treatment system 23 comprises a housing 51 defining an interiorspace 53 of the chamber through which liquid delivered to the chamberflows from the inlet end 25 to the outlet end 27 thereof. The housing 51suitably comprises an elongate tube 55 generally defining, at least inpart, a sidewall 57 of the chamber 21. In the illustrated embodiment,the housing 51 further comprises an inlet collar 61 connected to andmounted on one end of the tube 55 to define the inlet end 25 of thechamber 21.

The housing 51 also comprises a closure 63 connected to andsubstantially closing the longitudinally opposite end of the sidewall57, and having at least one outlet port 65 (broadly, an outlet) thereinto generally define the outlet end 27 of the treatment chamber 21. Theclosure 63 also has a screen element 66 held in assembly therewith andblocking the outlet port 65 (e.g., between the outlet port and theinterior space 53 of the chamber 21) to inhibit the chamber particles 24from flowing out of the chamber through the outlet port along with theliquid solution. The sidewall 57 (e.g., defined by the elongate tube 55)of the chamber 21 has an inner surface 67 that together with the collar61 and the closure 63 define the interior space 53 of the chamber.

In the illustrated embodiment, the tube 55 is generally cylindrical sothat the chamber sidewall 57 is generally annular in cross-section.However, it is contemplated that the cross-section of the chambersidewall 57 may be other than annular, such as polygonal or anothersuitable shape, and remain within the scope of this invention. Thechamber sidewall 57 of the illustrated chamber 21 is suitablyconstructed of a transparent material, although it is understood thatany suitable material may be used as long as the material is compatiblewith the liquid components being treated in the chamber, the pressure atwhich the chamber is intended to operate, and other environmentalconditions within the chamber such as temperature.

With particular reference to FIG. 3B, the inlet collar 61 at the inletend 25 of the chamber 21 is generally annular and has at least one, andmore suitably a plurality of inlet ports 69 a, 69 b (broadly, an inlet)formed therein for receiving liquid solution components into theinterior space 53 of the chamber 21. At least one inlet port 69 a isoriented generally tangentially relative to the annular collar 61 sothat liquid flows into the interior space 53 of the chamber 21 generallytangentially thereto to impart a swirling action to liquid as it entersthe chamber. More suitably, in the illustrated embodiment a pair ofinlet ports 69 a, 69 b are arranged in parallel alignment with each andextend generally tangentially relative to the annular collar 61, withone port 69 a being designated herein as the outer inlet port and theother port 69 b being designated the inner inlet port.

This dual tangential inlet port 69 a, 69 b arrangement is particularlyuseful for initiating mixing of two or more components together beforethe liquid solution is further subjected to ultrasonic treatment withinthe chamber 21. In a particularly suitable use of this arrangement,where the liquid to be treated in the chamber 21 comprises two or moreliquids, the liquid having the lowest viscosity is directed to flow intothe chamber via the outer inlet port 69 a while the liquid having thehighest viscosity is directed to flow into the chamber via the innerinlet port 69 b. The flow of the lower viscosity ingredient through theouter inlet port 69 a has a tendency to draw the higher viscosityingredient into the interior space 53 of the chamber 21 to speed therate at which the higher viscosity ingredient is introduced into thechamber.

This action, combined with the swirling action resulting from thetangential direction in which the liquid components are directed intothe chamber 21, facilitate an initial mixing of these two componentsbefore the liquid solution flows further through the chamber forultrasonic treatment. In the illustrated embodiment, the collar 61 alsohas an additional tangential set of inlet ports 69 a, 69 b and a pair ofgenerally vertically oriented inlet ports 71. It is understood, however,that none of the ports 69 a, 69 b need to be oriented tangentiallyrelative to the collar 61 to remain within the scope of this invention.It is also understood that the number of inlet ports 69 a, 69 b, 71 mayvary, and may even be limited to a single inlet port.

An ultrasonic waveguide assembly, generally indicated at 101, extendslongitudinally at least in part within the interior space 53 of thechamber 21 to ultrasonically energize liquid (and any other componentsof the liquid solution) flowing through the interior space 53 of thechamber, as well to ultrasonically energize the chamber particles 24. Inparticular, the ultrasonic waveguide assembly 101 of the illustratedembodiment extends longitudinally from the lower or inlet end 25 of thechamber 21 up into the interior space 53 thereof to a terminal end 103of the waveguide assembly disposed intermediate the inlet ports 69 a, 69b and the outlet port 65. More suitably, the waveguide assembly 101 ismounted, either directly or indirectly, to the chamber housing 51 aswill be described later herein.

The ultrasonic waveguide assembly 101 suitably comprises an elongatehorn assembly, generally indicated at 105, disposed entirely with theinterior space 53 of the housing 51 intermediate the uppermost inletport and the outlet port for complete submersion within the liquid beingtreated within the chamber 21, and more suitably it is aligned coaxiallywith the chamber sidewall 57. The horn assembly 105 has an outer surface107 that together with the inner surface 67 of the sidewall 57 defines aflow path within the interior space 53 of the chamber 21 along whichliquid and other components flow past the horn assembly within thechamber (this portion of the flow path being broadly referred to hereinas the ultrasonic treatment zone). The horn assembly 105 has an upperend 109 defining a terminal end of the horn assembly (and therefore theterminal end 103 of the waveguide assembly) and a longitudinallyopposite lower end 111. The waveguide assembly 101 of the illustratedembodiment also comprises a booster 113 coaxially aligned with andconnected at an upper end thereof to the lower end 111 of the hornassembly 105. It is understood, however, that the waveguide assembly 101may comprise only the horn assembly 105 and remain within the scope ofthis invention. It is also contemplated that the booster 113 may bedisposed entirely exterior of the chamber housing 51, with the hornassembly 105 mounted on the chamber housing 51 without departing fromthe scope of this invention.

The ultrasonic waveguide assembly 101, and more particularly the booster113 in the illustrated embodiment of FIG. 3, is suitably mounted on thechamber housing 51, e.g., on the tube 55 defining the chamber sidewall57, at the upper end thereof by a mounting member 115 that is configuredto vibrationally isolate the waveguide assembly (which vibratesultrasonically during operation thereof) from the ultrasonic treatmentchamber housing. That is, the mounting member 115 inhibits the transferof longitudinal and transverse mechanical vibration of the waveguideassembly 101 to the chamber housing 51 while maintaining the desiredtransverse position of the waveguide assembly (and in particular thehorn assembly 105) within the interior space 53 of the chamber housingand allowing both longitudinal and transverse displacement of the hornassembly within the chamber housing. In the illustrated embodiment, themounting member 115 also at least in part (e.g., along with the booster113) closes the inlet end 25 of the chamber 21.

As one example, the mounting member 115 of the illustrated embodimentgenerally comprises an annular outer segment 117 extending transverse tothe waveguide assembly 101 in transversely spaced relationshiptherewith, and a flange member 119 interconnecting the outer segment tothe waveguide assembly. While the flange member 119 and transverse outersegment 117 of the mounting member 115 extend continuously about thecircumference of the waveguide assembly 101, it is understood that oneor more of these elements may be discontinuous about the waveguideassembly such as in the manner of wheel spokes, without departing fromthe scope of this invention. The outer segment 117 of the mountingmember 115 is particularly configured to seat down against a shoulder121 formed by the inlet collar 61.

As seen best in FIG. 3A, the internal cross-sectional dimension (e.g.,internal diameter) of the collar 61 is stepped outward as the collarextends longitudinally downward away from the chamber sidewall 57 toaccommodate the flange member 119. In one particularly suitableembodiment, the collar 61 is sufficiently sized to be transverselyspaced from the flange member 119 to define a generally annular gap 123therebetween in which liquid delivered to the chamber 21 via the inletports 69 a, 69 b of the collar enters the interior space 53 of thechamber. This annular gap 123 further facilitates the swirling action ofthe liquid upon entry into the chamber 21 via the collar inlet ports 69a, 69 b.

The mounting member 115 is suitably sized in transverse cross-section sothat at least an outer edge margin of the outer segment 117, and moresuitably a substantial transverse portion of the outer segment is seatedon the shoulder 121 formed on the collar 61. A suitable fastening system(not shown), such as a plurality of bolts and corresponding nuts (notshown), secures the outer segment 117 of the mounting member 115 to theshoulder 121 formed by the collar 61 to thereby connect the booster 113(and more broadly the waveguide assembly 101) to the chamber housing 51.

The flange member 119 may suitably be constructed relatively thinnerthan the outer segment 117 of the mounting member 115 to facilitateflexing and/or bending of the flange member 119 in response toultrasonic vibration of the waveguide assembly 101. As an example, inone embodiment the thickness of the flange member 119 may be in therange of about 0.2 mm to about 5 mm, and more suitably about 2.5 mm. Theflange member 119 of the illustrated mounting member 115 suitably has aninner transverse component 125 connected to the waveguide assembly 101and extending generally transversely outward therefrom but inward of theouter segment 117 of the mounting member, and an axial, or longitudinalcomponent 127 interconnecting the transverse inner component with theouter segment of the mounting member and together with the transverseinner component generally forming a generally L-shaped cross-section ofthe flange member 119. It is contemplated, however, that the flangemember 119 may instead have a generally U-shaped cross-section or othersuitable cross-sectional shape such as an H-shape, an I-shape, aninverted U-shape and the like and remain within the scope of thisinvention. Additional examples of suitable mounting member 115configurations are illustrated and described in U.S. Pat. No. 6,676,003,the entire disclosure of which is incorporated herein by reference tothe extent it is consistent herewith.

The longitudinal component 127 of the illustrated flange member 119 issuitably cantilevered to the transverse outer segment 117 and to thetransverse inner component 125 of the flange member, while the innercomponent of the flange member is cantilevered to the waveguide assembly101. Accordingly, the flange member 119 is capable of dynamicallybending and/or flexing relative to the outer segment 117 of the mountingmember 115 in response to vibratory displacement of the waveguideassembly 101 to thereby isolate the chamber housing 51 from transverseand longitudinal displacement of the waveguide assembly.

While in the illustrated embodiment the transverse outer segment 117 ofthe mounting member 115 and the transverse inner component 125 of theflange member 119 are disposed generally at longitudinally offsetlocations relative to each other, it is understood that they may bedisposed at generally the same location (e.g., where the flange memberis generally U-shaped in cross-section) or at locations other than thoseillustrated in FIG. 3) without departing from the scope of thisinvention.

In one particularly suitable embodiment the mounting member 115 is ofsingle piece construction. Even more suitably the mounting member 115may be formed integrally with the booster 113 (and more broadly with thewaveguide assembly 101) as illustrated in FIG. 3. However, it isunderstood that the mounting member 115 may be constructed separate fromthe waveguide assembly 101 and remain within the scope of thisinvention. It is also understood that one or more components of themounting member 115 may be separately constructed and suitably connectedor otherwise assembled together.

In one suitable embodiment the mounting member 115 is furtherconstructed to be generally rigid (e.g., resistant to staticdisplacement under load) so as to hold the waveguide assembly 101 inproper alignment within the interior space 53 of the chamber 21. Forexample, the rigid mounting member 115 in one embodiment may beconstructed of a non-elastomeric material, more suitably metal, and evenmore suitably the same metal from which the booster 113 (and morebroadly the waveguide assembly 101) is constructed. The term rigid isnot, however, intended to mean that the mounting member 115 is incapableof dynamic flexing and/or bending in response to ultrasonic vibration ofthe waveguide assembly 101. In other embodiments, the rigid mountingmember 115 may be constructed of an elastomeric material that issufficiently resistant to static displacement under load but isotherwise capable of dynamic flexing and/or bending in response toultrasonic vibration of the waveguide assembly 101. While the mountingmember 115 illustrated in FIG. 3 is constructed of a metal, and moresuitably constructed of the same material as the booster 113, it iscontemplated that the mounting member may be constructed of othersuitable generally rigid materials without departing from the scope ofthis invention.

A suitable ultrasonic drive system 131 (shown schematically in FIG. 1)including at least an exciter (not shown) and a power source (not shown)is disposed exterior of the chamber 21 and operatively connected to thebooster 113 (and more broadly to the waveguide assembly 101) to energizethe waveguide assembly to mechanically vibrate ultrasonically. Examplesof suitable ultrasonic drive systems 131 include a Model 20A3000 systemavailable from Dukane Ultrasonics of St. Charles, Ill., and a Model2000CS system available from Herrmann Ultrasonics of Schaumberg, Ill.

The drive system 131 is suitably capable of operating the waveguideassembly 101 at a frequency in the range of about 15 kHz to about 100kHz, more suitably in the range of about 15 kHz to about 60 kHz, andeven more suitably in the range of about 20 kHz to about 40 kHz. Suchultrasonic drive systems 131 are well known to those skilled in the artand need not be further described herein.

With particular reference to FIG. 3, the horn assembly 105 comprises anelongate, generally cylindrical horn 133 having an outer surface 135,and two or more (i.e., a plurality of) agitating members 137 connectedto the horn and extending at least in part transversely outward from theouter surface of the horn in longitudinally spaced relationship witheach other. The horn 133 is suitably sized to have a length equal toabout one-half of the resonating wavelength (otherwise commonly referredto as one-half wavelength) of the horn. In one particular embodiment,the horn 133 is suitably configured to resonate in the ultrasonicfrequency ranges recited previously, and most suitably at 20 kHz. Forexample, the horn 133 may be suitably constructed of a titanium alloy(e.g., Ti6Al4V) and sized to resonate at 20 kHz. The one-half wavelengthhorn 133 operating at such frequencies thus has a length (correspondingto a one-half wavelength) in the range of about 4 inches to about 6inches, more suitably in the range of about 4.5 inches to about 5.5inches, even more suitably in the range of about 5.0 inches to about 5.5inches, and most suitably a length of about 5.25 inches (133.4 mm). Itis understood, however, that the ultrasonic treatment chamber 21 mayinclude a horn assembly 105 in which the horn 133 is sized to have anyincrement of one-half wavelength without departing from the scope ofthis invention.

In the illustrated embodiment, the agitating members 137 comprise aseries of six washer-shaped rings that extend continuously about thecircumference of the horn member 133 in longitudinally spacedrelationship with each other and transversely (e.g., radially in theillustrated embodiment) outward from the outer surface of the horn. Inthis manner the vibrational displacement of each of the agitatingmembers 137 relative to the horn 133 is relatively uniform about thecircumference of the horn. It is understood, however, that the agitatingmembers 137 need not each be continuous about the circumference of thehorn 133. For example, the agitating members 137 may instead be in theform of spokes, blades, fins or other discrete structural members thatextend transversely outward from the outer surface 135 of the horn 133.

To provide a dimensional example, for the horn 133 of the illustratedembodiment of FIG. 3 having a length of about 5.25 inches (133.4 mm),one of the rings 137 is suitably disposed adjacent the terminal end ofthe horn 133 (and hence of the waveguide assembly 101), and moresuitably is longitudinally spaced approximately 0.063 inches (1.6 mm)from the terminal end of the horn member. In other embodiments theuppermost ring 137 may be disposed at the terminal end of the horn andremain within the scope of this invention. The rings 137 are each about0.125 inches (3.2 mm) in thickness and are longitudinally spaced fromeach other (between facing surfaces of the rings) a distance of about0.875 inches (22.2 mm).

It is understood that the number of agitating members 137 (e.g., therings in the illustrated embodiment) may be less than or more than sixwithout departing from the scope of this invention. It is alsocontemplated that in other embodiments the agitating members 137 may beomitted entirely without departing from the scope of this invention, thehorn outer surface 135 providing the sole mechanical ultrasonicvibration contact with the liquid in the flow path within the treatmentchamber 21. It is further understood that the longitudinal spacingbetween the agitating members 137 may be other than as illustrated inFIG. 3 and described above (e.g., either closer or spaced furtherapart). While the rings 137 illustrated in FIG. 3 are equallylongitudinally spaced from each other, it is alternatively contemplatedthat where more than two agitating members are present the spacingbetween longitudinally consecutive agitating members need not be uniformto remain within the scope of this invention.

In particular, the locations of the agitating members 137 are at leastin part a function of the intended vibratory displacement of theagitating members upon vibration of the horn 133. For example, in theillustrated embodiment the horn 133 has a nodal region located generallylongitudinally centrally of the horn (e.g., between the third and fourthrings). As used herein, the “nodal region” of the horn 133 refers to alongitudinal region or segment of the horn member along which little (orno) longitudinal displacement occurs during ultrasonic vibration of thehorn and transverse (e.g., radial in the illustrated embodiment)displacement of the horn is generally maximized. Transverse displacementof the horn 133 suitably comprises transverse expansion of the horn butmay also include transverse movement (e.g., bending) of the horn.

In the illustrated embodiment, the configuration of the one-halfwavelength horn 133 is such that the nodal region is particularlydefined by a nodal plane (i.e., a plane transverse to the horn member atwhich no longitudinal displacement occurs while transverse displacementis generally maximized). This plane is also sometimes referred to as anodal point. Accordingly, agitating members 137 (e.g., in theillustrated embodiment, the rings) that are disposed longitudinallyfurther from the nodal region of the horn 133 will experience primarilylongitudinal displacement while agitating members that arelongitudinally nearer to the nodal region will experience an increasedamount of transverse displacement and a decreased amount of longitudinaldisplacement relative to the longitudinally distal agitating members.

It is understood that the horn 133 may be configured so that the nodalregion is other than centrally located longitudinally on the horn memberwithout departing from the scope of this invention. It is alsounderstood that one or more of the agitating members 137 may belongitudinally located on the horn so as to experience both longitudinaland transverse displacement relative to the horn upon ultrasonicvibration of the horn assembly 105.

Still referring to FIG. 3, the agitating members 137 are sufficientlyconstructed (e.g., in material and/or dimension such as thickness andtransverse length, which is the distance that the agitating memberextends transversely outward from the outer surface 135 of the horn 133)to facilitate dynamic motion, and in particular dynamic flexing/bendingof the agitating members in response to the ultrasonic vibration of thehorn member. In one particularly suitable embodiment, for a givenultrasonic frequency at which the waveguide assembly 101 is to beoperated in the ultrasonic chamber (otherwise referred to herein as thepredetermined frequency of the waveguide assembly) and a particularliquid to be treated within the chamber 21, the agitating members 137and horn 133 are suitably constructed and arranged to operate theagitating members in what is referred to herein as an ultrasoniccavitation mode at the predetermined frequency.

As used herein, the ultrasonic cavitation mode of the agitating membersrefers to the vibrational displacement of the agitating memberssufficient to result in cavitation (i.e., the formation, growth, andimplosive collapse of bubbles in a liquid) of the liquid being treatedat the predetermined ultrasonic frequency. For example, where the liquidflowing within the chamber comprises an aqueous solution, and moreparticularly water, and the ultrasonic frequency at which the waveguideassembly 101 is to be operated (i.e., the predetermined frequency) isabout 20 kHZ, one or more of the agitating members 137 are suitablyconstructed to provide a vibrational displacement of at least 1.75 mils(i.e., 0.00175 inches, or 0.044 mm) to establish a cavitation mode ofthe agitating members. It is understood that the waveguide assembly 101may be configured differently (e.g., in material, size, etc.) to achievea desired cavitation mode associated with the particular liquid beingtreated. For example, as the viscosity of the liquid being treatedchanges, the cavitation mode of the agitating members may need to bechanged.

In particularly suitable embodiments, the cavitation mode of theagitating members corresponds to a resonant mode of the agitatingmembers whereby vibrational displacement of the agitating members isamplified relative to the displacement of the horn. However, it isunderstood that cavitation may occur without the agitating membersoperating in their resonant mode, or even at a vibrational displacementthat is greater than the displacement of the horn, without departingfrom the scope of this invention.

In one suitable dimensional example, a ratio of the transverse length ofat least one and more suitably all of the agitating members 137 to thethickness of the agitating member is in the range of about 2:1 to about6:1. As another example, the rings 137 illustrated in FIG. 3 each extendtransversely outward from the outer surface 135 of the horn 133 a lengthof about 0.5 inches (12.7 mm) and the thickness of each ring is about0.125 inches (3.2 mm), so that the ratio of transverse length tothickness of each ring is about 4:1. It is understood, however that thethickness and/or the transverse length of the agitating members 137 maybe other than that of the rings illustrated in FIG. 3 without departingfrom the scope of this invention. Also, while the agitating members 137(rings) of the illustrated embodiment each have the same transverselength and thickness, it is understood that the agitating members mayhave different thicknesses and/or transverse lengths.

In the illustrated embodiment, the transverse length of the agitatingmember 137 also at least in part defines the size (and at least in partthe direction) of the flow path along which liquid or other flowablecomponents in the interior space 53 of the chamber 21 flows past thehorn assembly 105. For example, the horn 133 illustrated in FIG. 3 has aradius of about 0.875 inches (22.2 mm) and the transverse length of eachring 137 is, as discussed above, about 0.5 inches (12.7 mm). The radiusof the inner surface 67 of the housing sidewall 57 is approximately 1.75inches (44.5 mm) so that the transverse spacing between each ring andthe inner surface of the housing sidewall is about 0.375 inches (9.5mm). It is contemplated that the spacing between the horn outer surface135 and the inner surface 67 of the chamber sidewall 57 and/or betweenthe agitating members 137 and the inner surface of the chamber sidewallmay be greater or less than described above without departing from thescope of this invention.

In general, the horn 133 may be constructed of a metal having suitableacoustical and mechanical properties. Examples of suitable metals forconstruction of the horn 133 include, without limitation, aluminum,monel, titanium, stainless steel, and some alloy steels. It is alsocontemplated that all or part of the horn 133 may be coated with anothermetal such as silver, platinum and copper to mention a few. In oneparticularly suitable embodiment, the agitating members 137 areconstructed of the same material as the horn 133, and are more suitablyformed integrally with the horn. In other embodiments, one or more ofthe agitating members 137 may instead be formed separate from the horn133 and connected thereto to form the horn assembly 105.

While the agitating members 137 (e.g., the rings) illustrated in FIG. 3are relatively flat, i.e., relatively rectangular in cross-section, itis understood that the rings may have a cross-section that is other thanrectangular without departing from the scope of this invention. The termcross-section is used in this instance to refer to a cross-section takenalong one transverse direction (e.g., radially in the illustratedembodiment) relative to the horn outer surface 135). Additionally,although the agitating members 137 (e.g., the rings) illustrated in FIG.3 are constructed only to have a transverse component, it iscontemplated that one or more of the agitating members may have at leastone longitudinal (e.g., axial) component to take advantage of transversevibrational displacement of the horn (e.g., at and near the nodal regionof the horn illustrated in FIG. 3) during ultrasonic vibration of thewaveguide assembly 101.

For example, FIG. 4 illustrates one alternative embodiment of a hornassembly 205 having five agitating members 237 extending transverselyoutward from the outer surface 235 of the horn 233. While each of theagitating members 237 has a transverse component, e.g., in the form of aring similar to those of FIG. 3, the centermost agitating member 237also has an annular longitudinal component 241 secured to the transversecomponent. In particular, the centermost agitating member 237 isdisposed longitudinally generally at the nodal region, and moreparticularly at the nodal plane of the horn 233 in the illustratedembodiment of FIG. 4, where the transverse displacement of the horn 233is generally maximized during ultrasonic energization thereof whilelongitudinal displacement is generally minimized. The longitudinalcomponent 241 is thus capable of dynamic motion (e.g., flexing/bending)in a transverse direction in response to transverse displacement of thehorn 233 upon ultrasonic energization of the horn.

It is contemplated that the longitudinal component 241 need not extendentirely longitudinal, i.e., parallel to the outer surface of the horn233, as long as the longitudinal component has some longitudinal vectorto it. Also, while in the illustrated embodiment the agitating member237 having the longitudinal component 241 is generally T-shaped incross-section, it is understood that other configurations of such anagitating member are suitable, such as an L-shaped cross-section (withthe longitudinal component extending either up or down), a plus-shapedcross-section, or other suitable cross-section. It is also contemplatedthat one or more holes may formed in the centermost agitating member237, such as in the transverse component and/or the longitudinalcomponents 241 to allow fluid to flow freely in both the horizontal andvertical direction through this member.

As best illustrated in FIG. 3, the terminal end 103 of the waveguideassembly 101 (e.g., the end 109 of the horn 133 in the illustratedembodiment) is substantially spaced longitudinally from the outlet port65 (broadly, the outlet) at the outlet end 27 of the chamber 21 toprovide what is referred to herein as a buffer zone (i.e., the portionof the interior space 53 of the chamber housing 51 longitudinally beyondthe terminal end 103 of the waveguide assembly 101) to allow a moreuniform mixing or flow as liquid flows downstream of the terminal end103 of the waveguide assembly 101 to the outlet end 27 of the chamber.For example, in one suitable embodiment the buffer zone has a voidvolume (i.e., the volume of that portion of the open space 53 within thechamber housing 51 within the buffer zone) in which the ratio of thisbuffer zone void volume to the void volume of the remainder of thechamber housing interior space upstream of the terminal end of thewaveguide assembly is suitably in the range of about 0.01:1 to about5.0:1, and more suitably about 1:1.

Providing the illustrated buffer zone is particularly useful where thechamber 21 is used for mixing two or more components together to form aliquid solution such as in the system 23 of FIG. 1. That is, thelongitudinal spacing between the terminal end 103 of the waveguideassembly 101 and the outlet port 65 of the chamber 21 providessufficient space for the agitated flow of the mixed liquid solution togenerally settle prior to the liquid solution exiting the chamber viathe outlet port. This is particularly useful where, as in theillustrated embodiment, one of the agitating members 137 is disposed ator adjacent the terminal end of the horn 133. While such an arrangementleads to beneficial back-mixing of the liquid as it flows past theterminal end of the horn 133, it is desirable that this agitated flowsettle out at least in part before exiting the chamber. It isunderstood, however, that the terminal end 103 of the waveguide assembly101 within the interior space 53 of the chamber 21 may be disposedlongitudinally nearer to the outlet port 65 at the outlet end 27 of thechamber, or that the buffer zone may even be substantially entirelyomitted, without departing from the scope of this invention.

The opposite, e.g., more proximal end of the horn assembly 105 issuitably spaced longitudinally from the collar 61 to define what isreferred to herein as a liquid intake zone in which initial swirling ofliquid within the interior space 53 of the chamber housing 51 occursupstream of the horn assembly 105. This intake zone is particularlyuseful where the treatment chamber 21 is used for mixing two or morecomponents together whereby initial mixing is facilitated by theswirling action in the intake zone as the components to be mixed enterthe chamber housing 51. It is understood, though, that the proximal endof the horn assembly 105 may be nearer to the collar 61 than isillustrated in FIG. 3, and may be substantially adjacent to the collarso as to generally omit the intake zone, without departing from thescope of this invention.

In a particularly suitable embodiment the ultrasonic treatment chamber21 further comprises a standing wave member, generally indicated at 301,in the form of a reflector. The “standing wave member” is intended torefer to a member other than the waveguide assembly 101 that togetherwith the waveguide assembly generates a standing wave therebetweenwithin the chamber housing 51. The reflector 301 is disposed within theinterior space 53 of the chamber 21 and more particularly in the bufferzone between the terminal end 103 of the waveguide assembly 101 and theoutlet port 65 of the chamber 21 in longitudinally spaced, opposedrelationship with the terminal end of waveguide assembly. The locationof the reflector 301 in the chamber 21 is also such that the reflectoris spaced longitudinally from (e.g., below in the illustratedembodiment) the outlet port 65 and more suitably the screen element 66of the closure 63. Upon ultrasonic operation of the waveguide assembly101, the reflector 301 acts in conjunction with the waveguide assembly(which acts in this instance as an ultrasonic transducer) to produce astanding acoustic wave within the buffer zone, and more particularlybetween the terminal end 103 of the waveguide assembly and thereflector.

It is contemplated that instead of the reflector 301, the standing wavemember may be another wave generator, such as a transducer spaced fromthe waveguide assembly in opposed relationship therewith and operable togenerate ultrasonic acoustic wave energy that travels in a directionopposite the wave energy generated by the waveguide assembly to togetherwith the waveguide assembly produce a standing acoustic wavetherebetween.

In a particularly suitable embodiment the reflector 301 and waveguideassembly 101 produce a standing acoustic wave therebetween that has atleast one node, and which has no node at or adjacent the outlet port 65and more suitably at or adjacent the screen element 65. That is, anynode of the standing wave is spaced longitudinally from at least theoutlet port 65 and more suitably from the screen element 66 of theclosure 63. For example, the longitudinal spacing between the terminalend 103 of the waveguide assembly 101 and the reflector 301 suitablycorresponds to one-half of an acoustic wavelength λ (i.e., a one-halfwavelength) wherein the wavelength λ of the standing wave is a functionof the liquid flowing within the buffer zone in the chamber 21 and thefrequency at which the waveguide assembly (acting as a transducer) isoperated. In particular,

λ=c/f

where;

c=the speed of sound through the liquid in the chamber 21, and

f=the operating frequency of the waveguide assembly 101.

In the illustrated embodiment, the position of the reflector 301 issuitably adjustable longitudinally relative to the terminal end 103 ofthe waveguide assembly 101 to adjust the longitudinal spacing betweenthe reflector and the waveguide assembly. This allows the reflector 301to be selectively positioned relative to the waveguide assembly 101,depending on the liquid solution being treated and/or the predeterminedoperating frequency of the waveguide assembly, so as to generate aone-half wavelength standing wave (or a multiple of a one-halfwavelength standing wave). In particular, a support frame 303 comprisedof two or more support posts 305 extends through the closure 63 downinto the interior space 53 of the chamber 21, e.g., past the outlet port65 and more suitably past the screen element 66 of the closure and isadjustably moveable longitudinally relative to the closure. Thereflector 301 is suitably secured to the support frame 303 for conjointmovement with the support frame relative to the closure 63 and waveguideassembly 101. The support frame 303 may be manually adjustable ormechanically adjustable by a suitable adjustment mechanism (not shown).

The reflector 301 of the illustrated embodiment comprises a generallycircular solid plate sized for sufficiently spaced relationship with thechamber sidewall 57 so that the reflector does not substantially reducethe flow rate of liquid through the screen element 66 and outlet port65. The reflector 301 is suitably constructed from a material that hasan acoustic impedance greater than that of the liquid flowing within thechamber 21 (e.g., the liquid in which the standing wave is generated),and more suitably substantially greater. For example, in one embodimentthe reflector 301 may be constructed from stainless steel. It isunderstood, however, however that the reflector 301 may be constructedfrom any suitable material having an impedance greater than that of theliquid in the chamber 21 and remain within the scope of this invention.It is also contemplated that the reflector 301 may be other thanplate-shaped and/or other than circular without departing from the scopeof this invention.

As illustrated in FIG. 3, the chamber particles 24 are suitably disposedwithin the interior space 53 of the chamber 21 to a level below (i.e.,upstream from) the reflector 301, and more suitably below (or upstreamfrom) the terminal end 103 of the waveguide assembly 101 so that theparticles are not initially (e.g., prior to liquid flow through thechamber) disposed within the buffer zone. While the chamber particles 24are most suitably spherical in shape, it is contemplated that theparticles may be of any shape without departing from the scope of thisinvention. It is also contemplated that the particles 24 may becomprised of any suitable material depending on the intended function(e.g., adsorbent, filtering, agitating, etc.) of the particles. Somenon-limiting examples of suitable particle materials include silica,alumina, titania (titanium dioxide), carbon, mica, copper, iron, nickel,zinc, titanium, corundum (silicon carbide) and ceramic. It is alsocontemplated the surfaces of the particles may be modified to impartadditional characteristics thereto. As one example of suitableparticles, co-pending U.S. application Ser. No. 11/530,210, entitledDELIVERY SYSTEMS FOR DELIVERING FUNCTIONAL COMPOUNDS TO SUBSTRATES ANDPROCESSES OF USING THE SAME and filed Sep. 8, 2006, the entiredisclosure of which is incorporated herein by reference, discloses theuse of adsorbent particles such as silica or alumina particles to removedesired materials from the liquid flowing through the treatment chamber21.

In operation of the liquid treatment system 23 illustrated in FIG. 1,the one or more components 32 (with at least one of the components beinga liquid) are delivered (e.g., by the pumps 31 in the illustratedembodiment) via the conduits 33 to the inlet ports 69 a, 69 b formed inthe collar 61 of the treatment chamber housing 51. As these componentsenter the interior space 53 of the chamber 21 via the inlet ports 69 a,69 b, the orientation of the inlet ports induces a relatively swirlingaction to initiate mixing of these components upstream of the hornassembly 105, such as in the fluid intake zone of the interior space ofthe chamber. The liquid solution flows upward within the chamber 21 pastthe waveguide assembly 101 and through the bed of chamber particles 24between the waveguide assembly and the chamber sidewall 57.

The waveguide assembly 101, and more particularly the horn assembly 105,is driven by the drive system 131 to vibrate mechanically at apredetermined ultrasonic frequency. In response to ultrasonic excitationof the horn 133, the agitating members 137 that extend outward from theouter surface 135 of the horn 133 dynamically flex/bend relative to thehorn, or displace transversely (depending on the longitudinal positionof the agitating member relative to the nodal region of the horn). Whenusing a horn assembly 205 such as that illustrated in FIG. 4 with one ofthe agitating members 237 disposed at the nodal region of the horn andhaving a longitudinal 241 component spaced transversely from the horn,the longitudinal component of the agitating member dynamicallyflexes/bends transversely relative to the horn.

Liquid solution flows continuously longitudinally along the flow pathbetween the horn assembly 105 and the inner surface 67 of the chambersidewall 57 so that the ultrasonic vibration of the agitating members137 agitates the liquid solution (and, where liquid solution comprisestwo or more components, also facilitates mixing of the components). Inparticularly suitable embodiments, the dynamic motion of the agitatingmembers causes cavitation in the liquid to further facilitate agitationof the liquid solution. The ultrasonic energy imparted by the hornassembly 105 also acts on the chamber particles 24 to promote relativemotion of the particles and to inhibit the particles against packingtogether, i.e., to reduce the risk of reduced flow rate or pressure dropwithin the ultrasonic treatment chamber 21. The vibratory motionimparted to the particles 24 also reduces the hydrodynamic boundarylayer of around each particle to facilitate an increased reaction rate(where a reaction of the liquid components, or reaction between theliquid and the chamber particles such as adsorption, is intended tooccur) within the chamber 21.

Ultrasonic operation of the waveguide assembly 101 also generates(together with the reflector 301) a standing acoustic wave (e.g., a onedimensional standing wave) in the liquid within the buffer zone betweenthe terminal end 103 of the waveguide assembly and the reflector, withthe one or more nodes of the standing wave spaced longitudinally fromthe outlet port 65, and more particularly from the screen element 66.With particular reference to FIG. 5, as liquid flows up beyond theterminal end 103 of the waveguide assembly 101, it may carry some of thechamber particles 24 into the buffer zone. The acoustic radiation of thestanding wave around these particles 24 urges the particles toward thenearest dynamically stable position, which is the node of the one-halfwavelength standing wave (or node at each one-half wavelength if thedistance between the reflector 301 and waveguide assembly 101 is amultiple of a one-half wavelength). The particles 24 thus becomegenerally “trapped” at the node of the standing wave away from thescreen element 66 and outlet port 65 as illustrated in FIG. 5 to therebyinhibit the particles against clogging the screen element, and hence theoutlet port, or otherwise reducing the flow rate of liquid out of thechamber 21.

In some embodiments, particles 24 stabilized at the node of the standingwave will agglomerate. As such an agglomeration becomes heavier, theagglomerated particles will fall away from the node and back (e.g.,against the direction of flow through the chamber) down into the mainbed of particles in the chamber 21.

Where further agitation of the liquid in the chamber 21 is desired, abaffle assemble (not shown) can be disposed within the interior space 53of the chamber, and in particular generally transversely adjacent theinner surface 67 of the sidewall 57 and in generally transverselyopposed relationship with the horn assembly 105. Such a baffle assemblymay comprise one or more baffle members disposed adjacent the innersurface 67 of the chamber sidewall 57 and extending at least in parttransversely inward from the inner surface of the sidewall toward thehorn assembly 105 in interspaced relationship with the agitating members137. These baffle members facilitate the flow of liquid transverselyinward over the ultrasonically vibrated agitating members 137 of thehorn assembly 105. One suitable baffle assemble is described more fullyin co-pending U.S. application Ser. No. 11/530,311 entitled ULTRASONICLIQUID TREATMENT CHAMBER AND CONTINUOUS FLOW MIXING SYSTEM and filedSep. 8, 2006, the disclosure of which is incorporated herein byreference to the extent it is consistent herewith.

In another suitable embodiment, the sidewall 57 of the ultrasonictreatment chamber 21 may be configured and arranged relative to thewaveguide assembly 101 to generate a standing acoustic wave therebetweenupon ultrasonic vibration of the waveguide assembly. In particular, thechamber sidewall 57 may be constructed of a material having anacoustical impedance that is substantially greater than the liquidflowing within the chamber 21, and in particular along the flow pathbetween the waveguide assembly 101 and the chamber sidewall. The innersurface 67 of the sidewall 57 is suitably spaced from the outer surface135 of the ultrasonic horn 133 a distance sufficient (based on theliquid in the chamber 21 and the operating frequency of the waveguideassembly 101) to generate a one-half wavelength standing wave whereinthe outer surface of the horn acts as a transducer and the sidewall ofthe chamber acts as a reflector.

Upon operation of the waveguide assembly 101 a standing acoustic wave isproduced in the liquid between the horn outer surface 135 and thesidewall inner surface 67. Such a standing wave suitably has at leastone node spaced from the sidewall inner surface 67 and the horn outersurface 135. Chamber particles 24 in the flow path are urged toward andgenerally stabilized or trapped at the one or more nodes of the standingwave to inhibit particles against stagnating against the sidewall 57and/or against the horn 133, and to inhibit particles against beingcarried by the flow of liquid downstream beyond the terminal end 103 ofthe waveguide assembly 101 into the buffer zone.

In other embodiments, such as where the ultrasonic treatment chamber 21is used for mixing together two or more components to form a liquidsolution, it is contemplated that the chamber particles 24 may beomitted (e.g., the chamber would resemble what is illustrated in FIG. 2)without departing from the scope of this invention. In such embodiments,the longitudinal standing wave formed in the buffer zone of the chamber21 (i.e., by the waveguide assembly 101 and the reflector 301) is usedto trap small particulate contaminates that may be present in the liquidcomponents, thus effectively removing the contaminates from the liquidsolution before the solution exits the treatment chamber.

When introducing elements of the present invention or preferredembodiments thereof, the articles “a”, “an”, “the”, and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including”, and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

As various changes could be made in the above constructions and methodswithout departing from the scope of the invention, it is intended thatall matter contained in the above description and shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

1. An ultrasonic treatment chamber for ultrasonically treating a liquid,said treatment chamber comprising: an elongate housing havinglongitudinally opposite ends and an interior space, the housing beinggenerally closed at said longitudinal ends and having an inlet port forreceiving liquid into the interior space of the housing and an outletport through which liquid is exhausted from the housing followingultrasonic treatment of the liquid, the outlet port being spacedlongitudinally from the inlet port such that liquid flows longitudinallywithin the interior space of the housing from the inlet port to theoutlet port, an elongate ultrasonic waveguide assembly extendinglongitudinally within the interior space of the housing and beingoperable at a predetermined ultrasonic frequency to ultrasonicallyenergize liquid flowing within the housing, the waveguide assemblycomprising an elongate ultrasonic horn disposed intermediate the inletport and the outlet port of the housing and having an outer surfacelocated for contact with liquid flowing within the housing from theinlet port to the outlet port, the waveguide assembly having a terminalend spaced longitudinally from the outlet port of the housing; and astanding wave member disposed within the housing longitudinallyintermediate the outlet port of the housing and the terminal end of thewaveguide assembly, said standing wave member being spaced from theterminal end of the waveguide assembly so as to define an acousticstanding wave therebetween upon operation of the waveguide assembly atsaid predetermined ultrasonic frequency.
 2. The ultrasonic treatmentchamber set forth in claim 1 wherein the standing wave member comprisesa reflector.
 3. The ultrasonic treatment chamber set forth in claim 1wherein the waveguide assembly further comprises a plurality of discreteagitating members in contact with and extending transversely outwardfrom the outer surface of the horn intermediate the inlet port and theoutlet port in longitudinally spaced relationship with each other, theagitating members and the horn being constructed and arranged fordynamic motion of the agitating members relative to the horn uponultrasonic vibration of the horn at said predetermined frequency and tooperate in an ultrasonic cavitation mode of the agitating memberscorresponding to the predetermined frequency and the liquid beingtreated in the chamber.
 4. The ultrasonic treatment chamber set forth inclaim 1 further comprising a bed of particles disposed in the chambertransversely intermediate the waveguide assembly and the chamberhousing.
 5. The ultrasonic treatment chamber set forth in claim 4wherein the particles comprise at least one of silica, alumina, titania(titanium dioxide), carbon, mica, copper, iron, nickel, zinc, titanium,corundum (silicon carbide) and ceramic.
 6. The ultrasonic treatmentchamber set forth in claim 1 wherein the longitudinal position of thestanding wave member within the chamber is adjustable relative to thewaveguide assembly.
 7. The ultrasonic treatment chamber set forth inclaim 1 wherein the predetermined frequency is in the range of about 20kHz to about 40 kHz.
 8. The ultrasonic treatment chamber set forth inclaim 1 wherein the horn and agitating members together define a hornassembly of the waveguide assembly, the horn assembly being disposedentirely within the interior space of the housing.
 9. The ultrasonictreatment chamber set forth in claim 1 further comprising a mountingmember for mounting the waveguide assembly on the housing generally atone of said longitudinal ends thereof, the mounting member beingconstructed to substantially vibrationally isolate the housing from thewaveguide assembly.
 10. The ultrasonic treatment chamber set forth inclaim 1 wherein the horn has a length of approximately one-halfwavelength.
 11. The ultrasonic treatment chamber set forth in claim 1wherein the standing wave member is spaced from the terminal end of thewaveguide assembly a distance of approximately one-half wavelength. 12.The ultrasonic treatment chamber set forth in claim 1 wherein thehousing further comprises a closure at one of said longitudinal ends andhaving said outlet port therein, said closure having a screen memberintermediate the interior of the chamber and the outlet port.
 13. Anultrasonic treatment system for ultrasonically treating a liquid, saidtreatment system comprising: an elongate, generally tubular housinghaving longitudinally opposite ends and an interior space, the housinghaving an inlet for receiving liquid into the interior space of thehousing and an outlet through which liquid is exhausted from the housingfollowing ultrasonic treatment of the liquid, the outlet being spacedlongitudinally from the inlet such that liquid flows longitudinallywithin the interior space of the housing from the inlet to the outlet;an elongate ultrasonic horn extending longitudinally within the interiorspace of the housing intermediate the inlet and the outlet of thehousing; and a drive system operable to ultrasonically vibrate theultrasonic horn, the ultrasonic treatment system being configured suchthat operation of the drive system generates mechanical vibration of thehorn within the interior space of the housing and further generates astanding acoustic wave within said interior space of the housing. 14.The ultrasonic treatment system set forth in claim 13 further comprisinga bed of particles disposed in the chamber transversely intermediate theultrasonic horn and the housing.
 15. The ultrasonic treatment system setforth in claim 14 wherein the particles comprise at least one of silica,alumina, titania (titanium dioxide), carbon, mica, copper, iron, nickel,zinc, titanium, corundum (silicon carbide) and ceramic.
 16. Theultrasonic treatment system set forth in claim 13 wherein the standingacoustic wave is directed longitudinally within the interior space ofthe housing with a node of the standing wave spaced longitudinally fromthe outlet of said housing.
 17. The ultrasonic treatment system setforth in claim 13 further comprising a standing wave member in theinterior space of the housing longitudinally intermediate the outlet andthe ultrasonic horn whereby the standing acoustic wave is generatedbetween the ultrasonic horn and the standing wave member upon operationof the drive system.
 18. The ultrasonic treatment system set forth inclaim 17 wherein the standing wave member comprises a reflector.
 19. Theultrasonic treatment system set forth in claim 13 wherein thelongitudinal position of the standing wave member within the interiorspace of the housing is adjustable relative to the ultrasonic horn. 20.The ultrasonic treatment system set forth in claim 13 wherein the drivesystem is operable to vibrate the ultrasonic horn at a frequency in therange of about 20 kHz to about 40 kHz.
 21. The ultrasonic treatmentsystem set forth in claim 13 wherein the housing is configured andarranged relative to the ultrasonic horn to generate a standing acousticwave within said interior space of the housing between said housing andsaid ultrasonic horn with a node of the standing acoustic wave spacedfrom both the housing and the ultrasonic horn.
 22. The ultrasonictreatment system set forth in claim 13 wherein the ultrasonic horn has alength of approximately one-half wavelength.
 23. A process forultrasonically treating a liquid in an ultrasonic treatment chambercomprised of an elongate, generally tubular housing having an inlet andan outlet spaced longitudinally from the inlet, said process comprising:directing liquid into the housing at the housing inlet for longitudinalflow within the housing to the housing outlet; generating mechanicalultrasonic vibration within the housing in direct contact with theliquid flowing within the housing, said direct contact being upstream ofthe housing outlet; and generating a standing acoustic wave within thehousing with the standing acoustic wave having a node spacedlongitudinally from the housing outlet.
 24. The process set forth inclaim 23 further comprising forming a bed of particles in the housing inthe flow path of the liquid, the liquid flowing longitudinally throughthe bed of particles within said housing, subjecting the particles tothe mechanical ultrasonic vibration within the housing and trapping someof said particles at the node of the standing acoustic wave within thehousing.